1.1 本规程涵盖了进行腐蚀疲劳试验的程序，以获得 S-N ( 3.2.1 )金属植入材料的疲劳曲线或统计得出的疲劳强度值，或两者兼而有之。本规程描述了在37°C的盐水溶液和室温下的空气中，承受恒定振幅、周期性力函数的轴向加载疲劳试样的测试。植入材料的环境试验方法可适用于其他疲劳载荷模式，如弯曲或扭转。虽然本规程不适用于植入式组件或设备的疲劳试验，但它确实为在与生理条件相关的环境中使用标准样本进行疲劳试验提供了指南。 1.2 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。 每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 植入物，尤其是矫形器械，通常会受到动态力的影响。因此，植入材料必须在生理环境中具有高抗疲劳性。 4.1.1 本规程提供了在模拟生理环境中进行疲劳测试的程序。建议将环境试验箱中的轴向拉伸疲劳试验作为标准程序。轴向疲劳载荷应符合惯例 E466 和 E467 . 4.1.1.1 弯曲和旋转弯曲梁疲劳试验或扭转试验可在类似的环境单元中进行。 4.1.2 本规程旨在评估植入物使用或预计使用的材料的疲劳和腐蚀疲劳性能。本规程适用于研究不同材料处理和表面条件对植入材料疲劳行为的影响。 实际植入物的加载模式可能与本实践不同。确定植入物和植入物组件的疲劳行为可能需要考虑特定设计和加载模式的单独测试。 4.1.3 作为体液的替代品，0.9 % 建议将盐水溶液作为标准环境。各种林格溶液中的一种或体液的另一种替代品也可能适用于特定测试。然而，这些不同的解决方案可能不会给出相同的疲劳耐久性结果。氯离子是这些溶液中引发腐蚀疲劳的最关键成分。 4.1.4 由于植入物由高度耐腐蚀的材料制成，当通过光学显微镜或扫描电子显微镜进行检查时，可能无法检测到可见腐蚀。只有在高循环范围内的疲劳强度下降可能是明显的。 因此 S-N 应在试验溶液和空气中生成涵盖广泛疲劳载荷范围的曲线。比较在空气和盐水溶液中产生的疲劳曲线可能是评估盐水环境影响的唯一方法。 4.1.5 如果已经确定了材料系统的疲劳行为，则仅在选定的应力范围内测试材料特性或表面条件的修改就足够了。 4.1.6 建议的1赫兹加载频率对应于行走期间的负重频率。对于筛选测试，可以使用更高的测试频率；但必须认识到，更高的频率可能会影响结果。 4.1.7 标准条件概述- 对于实验室间比较，以下条件被视为标准试验。轴向张力- 用0.9英寸的圆柱形试样进行拉伸试验 % 37°C下的盐水溶液和室温下的空气，加载频率为1 Hz。

1.1 This practice covers the procedure for performing corrosion fatigue tests to obtain S-N ( 3.2.1 ) fatigue curves or statistically derived fatigue strength values, or both, for metallic implant materials. This practice describes the testing of axially loaded fatigue specimens subjected to a constant amplitude, periodic forcing function in saline solution at 37°C and in air at room temperature. The environmental test method for implant materials may be adapted to other modes of fatigue loading such as bending or torsion. While this practice is not intended to apply to fatigue tests on implantable components or devices, it does provide guidelines for fatigue tests with standard specimens in an environment related to physiological conditions. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 Implants, particularly orthopedic devices, are usually exposed to dynamic forces. Thus, implant materials must have high fatigue resistance in the physiological environment. 4.1.1 This practice provides a procedure for fatigue testing in a simulated physiological environment. Axial tension-tension fatigue tests in an environmental test chamber are recommended as a standard procedure. The axial fatigue loading shall comply with Practices E466 and E467 . 4.1.1.1 Bending and rotating bending beam fatigue tests or torsion tests may be performed in a similar environmental cell. 4.1.2 This practice is intended to assess the fatigue and corrosion fatigue properties of materials that are employed or projected to be employed for implants. This practice is suitable for studying the effects of different material treatments and surface conditions on the fatigue behavior of implant materials. The loading mode of the actual implants may be different from that of this practice. Determining the fatigue behavior of implants and implant components may require separate tests that consider the specific design and loading mode. 4.1.3 As a substitute for body fluid, 0.9 % saline solution is recommended as a standard environment. One of the various Ringer's solutions or another substitute for body fluid may also be suitable for particular tests. However, these various solutions may not give equal fatigue endurance results. The chloride ions are the most critical constituent in these solutions for initiating corrosion fatigue. 4.1.4 Because implants are manufactured from highly corrosion-resistant materials, no visible corrosion may be detectable when inspected by means of optical microscopy or scanning electron microscopy. Only a decrease of fatigue strength in the high cycle range may be noticeable. Therefore, S-N curves covering a broad fatigue loading range should be generated in the test solution and in air. Comparison of fatigue curves generated in air and saline solution may be the only way to assess the effect of the saline environment. 4.1.5 Where the fatigue behavior of a material system is already established, it may suffice to test modifications of the material properties or surface condition in only a selected stress range. 4.1.6 The recommended loading frequency of one hertz corresponds to the frequency of weight bearing during walking. For screening tests, higher test frequencies may be used; but it must be realized that higher frequencies may affect the results. 4.1.7 Summary of Standard Conditions— For inter-laboratory comparisons the following conditions are considered as the standard test. Axial tension-tension tests with cylindrical specimens in 0.9 % saline solution at 37°C and air at room temperature under a loading frequency of 1 Hz.